In order to call C++ code from C you may need to provide an API.
Below is and example of how it could be done.
// file lib.hpp -> this is the library private declaration file (C++)
class MyClass{
DoSomething();
};
// file lib.cpp -> this is the library private implementation file (C++)
MyClass::DoSomething(){
// do something implementation
}
// file: capi.h -> this file can be read by both C and C++ compilers
// for every class accessible from the outside create a struct
typedef struct MyLib_MyClass MyLib_MyClass
// use `extern "C"` to generate C compatible function names
#ifdef __cplusplus
extern "C"{
#endif
MyLib_DoSomething(MyLib_MyClass*);
#ifdef __cplusplus
}
#endif
// file: capi.cpp -> the implementation of the API, C++ file
// the extern "C" is always here because it's a cpp file
extern "C" {
#include "api.h"
#include "lib.hpp"
MyLib_DoSomething(MyLib_MyClass* arg){
// simply cast the pointer and then handle it as you would handle your normal objects!
auto ptr = reinterpret_cast<MyClass*>(arg);
ptr->DoSomething()
}
}
The main advantage of this method is that the cast works on any C++ class.
It can be namespace or template (you must specify all the template arguments though)
// cast with namespace
auto ptr = reinterpret_cast<MyNameSpace::MyClass*>(arg);
// cast with template (specify all of them!)
auto ptr = reinterpret_cast<MyClass<double,4>*>(arg);